Field
The present disclosure relates to a hybrid vehicle, and more specifically to a fail-safe running of a hybrid vehicle including an internal combustion engine (engine) as well as a first motor generator and a second motor generator which are connected through a planetary gear device to the engine. Description of the Background Art
A configuration in which an engine, a first motor generator, and a second motor generator are coupled by a planetary gear device is disclosed, as an example of the powertrain configuration of the hybrid vehicle, in Japanese Patent Laying-Open No. 2013-203116, for example. An electrical system of this hybrid vehicle is configured to include a converter capable of boosting an output voltage of a battery, and an inverter performing a bidirectional electric power conversion between the converter and the first and second motor generators.
According to Japanese Patent Laying-Open No. 2013-203116, when a malfunction of the inverter occurs, the hybrid vehicle runs in a fail-safe mode in which the inverter is kept in a gate shutoff state. Specifically, with each switching device of the inverter kept off, a rotational force of the engine mechanically (dynamically) rotates the first motor generator to cause a counter-electromotive voltage to be generated by the first motor generator. At this time, a braking torque is generated from the first motor generator and transmitted through the planetary gear device to act on an output shaft (a ring gear of the planetary gear device) in a forward direction (advance). In this way, a driving torque for the vehicle to run in the fail-safe mode is ensured.